Correlation between follicular fluid of 25-hydroxyvitamin D level and endocrine function, ovarian function and insulin resistance in women with polycystic ovary syndrome.

Abstract

This study was designed to reveal the profound association between follicular fluid vitamin D (25(OH)D) levels and the health status of women with polycystic ovary syndrome (PCOS), with the aim of laying a solid scientific foundation for the development of more precise treatment strategies for PCOS. By exploring the correlation between follicular 25(OH)D level and endocrine function, ovarian function and insulin resistance in women with PCOS, it is hoped that the potential value of this level in clinical practice can be realized. From June 2021 to March 2024, 153 women with infertility mainly due to PCOS were selected. According to the Rotterdam criteria, they were divided into phenotypes A-D, with 72 cases (47.06%), 36 cases (23.53%), 18 cases (11.76%), and 27 cases (17.65%), respectively. Forty-six healthy controls with gender and age matching were included. Endocrine function was evaluated by measuring follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and dehydroepiandrosterone sulfate. Ovarian function (ovarian volume and number of follicles) and insulin resistance index (HOMA-IR) were also assessed. PCOS patients with different phenotypes were divided into vitamin D deficiency (VDD) group (<20 ng/mL) and non-VDD group (≥20 ng/mL) according to 25(OH)D levels. The correlation between follicular fluid 25(OH)D and differential clinical features was evaluated. We found that 25(OH)D in follicular fluid of PCOS women was lower than that of controls (P<0.001). Phenotype A and B had higher LH and LH/FSH than phenotype D (P<0.05) and were hyperandrogenic, whereas phenotype D had normal or low androgens and no hyperandrogenic symptoms (P<0.05). In terms of ovarian function, PCOS women with phenotypes A, C, and D had large ovarian volumes, with more follicular fluid in A and C than in B (P<0.05). There were no significant differences in FBG, HOMA-IR, insulin sensitivity and follicular fluid 25-(OH)D among the four groups (P>0.05). In the phenotype A and B cohorts, the LH/FSH ratio, ovarian volume, and HOMA-IR of the VDD group were higher than those of the non-VDD group. There was a weak and negative correlation between follicular fluid 25(OH)D and LH/FSH levels and HOMA-IR, and a moderate correlation with ovarian volume. To sum up: PCOS women have lower follicular fluid 25(OH)D. When VDD is present, patients with phenotype A and B have higher levels of insulin resistance characteristics. Although follicular fluid 25-(OH)D does not show statistically significant differences across the different PCOS phenotypic cohorts, specific phenotypes A and B exhibit more pronounced insulin resistance profiles in those individuals with VDD.